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3. Atoms are excited, 1 photon is released, when the photon hits an excited atom 2 photons that are in step are released. Photons bounce off 2 mirrors making more photons. One mirror is 95% reflective, 5% gets out as a laser 3. Atoms are excited, 1 photon is released, when the photon hits an excited atom 2 photons that are in step are released. Photons bounce off 2 mirrors making more photons. One mirror is 95% reflective, 5% gets out as a laser

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4. If we add energy to light we should be able to start the photoelectric effect. If light is a wave, adding energy changes the brightness which does not control the photoelectric effect. If light is a particle, adding energy makes photons vibrate faster (frequency) which changes the color, which does control the photoelectric effect. Therefore light must be a particle according to Einstein. 4. If we add energy to light we should be able to start the photoelectric effect. If light is a wave, adding energy changes the brightness which does not control the photoelectric effect. If light is a particle, adding energy makes photons vibrate faster (frequency) which changes the color, which does control the photoelectric effect. Therefore light must be a particle according to Einstein.

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9. Electrons spin giving them a magnetic moment. Most often they come in pairs and cancel each other out, but an atom with an odd number of electrons will have a magnetic moment. This atom will influence the atoms around it to line up with it and make a domain. When all the domains line up the material is magnetic. 9. Electrons spin giving them a magnetic moment. Most often they come in pairs and cancel each other out, but an atom with an odd number of electrons will have a magnetic moment. This atom will influence the atoms around it to line up with it and make a domain. When all the domains line up the material is magnetic.